Whole mount preparation showing the vascularization of the cell body rich area of the dorsal root ganglia (DRG) vs. the dorsal and ventral roots and sciatic nerve at L4 in the C3H mouse. Bright-field photomicrograph of a whole-mount L4 DRG preparation for anatomical reference. Dashed line demarks the cell body-rich area from the sciatic nerve and dorsal and ventral spinal roots (A). Representative confocal micrograph of a mouse L4 DRG labeled with the endothelial cell marker CD31 showing the marked difference in the density of the vascular supply within the sensory ganglia as compared to the corresponding spinal nerve and dorsal root (B). This dense vascularization of the DRG along with the large fenestrations of the blood vessels in the DRG may partially explain why certain neurotoxics preferential accumulate in the DRG and produce a primarily sensory vs. motor neuropathy. The confocal image in (B) was assembled from 280 optical sections acquired at 0.5 μm z-plane intervals so that the total z stack is 140 μm-thick. Scale bar = 100 μm.